Measuring Sugar Content of a Liquid with a Laser Pointer

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Transcript of Measuring Sugar Content of a Liquid with a Laser Pointer

Measuring the Sugar Content of a Liquid using a Laser Pointer Your sitting theredrinking yoursugary beverage. You think to yourself"Could I measure theamount of sugar in mydrink with a laser?" Has this ever happened? No!?!? Never?!?! Well, here's the answer anyway! You must be wondering,"If I could use a laser to measurethe amount of sugar in my liquid, how would it be done?" Well! We would do this by measuring the liquid's index of refraction! "Spencer! What is an index of refraction?" I'm glad you asked! An index of refraction is the speed awave of light travels through the substanceinstead of through a vacuum. Problem: "How fast does light travel through a vacuum?" 299,792,458 meters per second. Hypothesis: If I increase the percentage of sugar in the liquid, then it's index of refraction will increase too. Variables:Dependant variable: liquid's IOR (index of refraction)Independant variable: amount of sugar in the liquid "Spencer, what is the liquid?" Good question! The liquid isDihydrogen Monoxide(water). The results of this experiment only apply to Dihydrogen Monoxide! "What materials would we use to conduct the experiment?" Let's look at the list! Materials:• (2) 1" × 3" glass microscope slides• diamond scribe or glass cutter• metric ruler• roll of electrical tape• epoxy cement (either 5-minute or 30-minute epoxy)• toothpicks• laser pointer• cardboard• roll of clear tape• paper• pencil• modeling clay• piece of string• (30g) sugar• (370ml) water• (100ml) graduated cylinder• gram scale• calculator with trigonometric functions (sine, arctangent) Procedures Step 1. Building the prism Cut the microscope slide and glue it together in a prism shape with the epoxy glue. Simple enough. Step 2. Measuring the IOR Shine the laser through the empty prism and mark points e,d,and b. Draw a line between points d and e. Fill the prism with the sugar water and shine the laser through again. Mark points f and a, point d should be the same. Extend a line from point a to f and continue till you cross the line between points d and e. Mark the intersection as point c. Measure line X(between point a and b) and line L(between point b and c) "Spencer! Do we realy need all of details! It's kind of dull." Hush! This is the short version! Now find the angle of minimum deviation. Use a calculator to find the arctangent of X/L. That is the agle of minimum deviation. IOR=2.00056*sin[1/2(angle of minimum deviation+60)] The answer will be the index of refraction. Data When the experiment was done, it reared data! "Data! Dear God, Not Data!" Yes! Data!Here are some charts and graphs. Notice that as the amount of C12H22O11(sugar) increases, the IOR also increases. Sound familiar? "Oh No. It's over already?" Yes, All that's left is the Conclusion. All you need to know for the conclusion is that the hypothesis was correct, and I'm going out on a limb here, and suggesting that the IOR would be altered if you dissolved pretty much anything in water. "That sounds like a reasonable enough coclusion. It's awfully short though." THE END Use this equation to find the IOR. Conclusion Well, it is the short version.